Apparatus for dosing powdered or granulated additives in water works, namely swimming pools

ABSTRACT

An apparatus for dosing a granulated or powdered additive in the water of a water works includes a dosing assembly ( 10 ) with a water collecting tank ( 9 ) hydraulically connected to inflows ( 20, 21 ) of unmixed water and to an outflow of additive-mixed water ( 33 ) to the works. Unmixed water is tapped through a duct ( 41 ) from an inflow and fed to a substantially tubular manifold ( 18 ), upwardly connected to tank ( 19 ). The additive is delivered into manifold ( 18 ), in which the additive mixes with water tapped from the inflow through duct ( 41 ) and additive-mixed water discharges into collecting tank ( 19 ).

DESCRIPTION

1. Field of the Invention

The present invention relates to an apparatus for dosing powdered orgranulated additives in water works, in particular, but not exclusively,suitable for use in the field of swimming pools.

2. Description of the Prior Art

It is known that in water works the need often arises for the additionof water with antibacterial and/or generally disinfectant substances.Such substances, usually available in granular form and namely inpowder, have to be dosed in a very precise and reliable way, in order toobtain the coverage required by the relevant hygienic regulations.

The problem is deeply felt in the case of swimming pools, chiefly publicones, where it is very difficult to guarantee wholly hygienicconditions, due to the organic pollution generated by swimmers,increased by the stagnant state of the water. On the other hand, thefulfilment of such conditions is fundamental to defend the swimmers'health, and in this viewpoint the relevant regulations are particularlysevere.

According to the method presently used in this field, the disinfectantpowder, typically based on calcium hypochlorite, or in any case onchlorine, is preliminarily dissolved in a separate tank Theadditive-mixed water is then taken out with suitable dosing pumps andfed to the main works. Apparatuses which operate according to thismethod are described in U.S. Pat. Nos. 3,456,801 and 3,807,700. Thismethod has some important drawbacks.

The first of them is that, being chlorine in general light-sensitive,when the additive-mixed water stays in the preliminary tank for longperiods, which can last even some days, its disinfectant powerdecreases. Such decrease can be approximately about 50% in just a singleweek of light exposure. Then, to guarantee the fulfilment of thechlorine-coverage requirements, it is necessary to use much moresubstance than that theorically required, with a remarkable costincrease for higher product consumptions.

In the second place, dosing pumps which feed additive-mixed water to themain works are subject to frequent occlusions and failures, withconsequent high costs for maintenance operations and/or replacements ofworn out components. In fact, as the, product is chemically attacking,the widths of the flow sections have to be kept very small, thisinvolving high flow speeds, with consequent increase of wearingphenomena. Such small sections are also easily clogged by calciumhypoclorite deposits.

A further drawback of the above described conventional method is thatthe workers having to carry out routine and unpredictable maintenanceoperations of the dosing system are forced to operate in troublesomeconditions, since water with a high additive concentration is remarkablytoxic.

Finally, in many cases the degree of chlorine coverage which can beobtained is unsatisfactory. As a matter of fact, when the system startsa very long transient condition occurs and several hours pass before theproduct has spread throughout the whole water volume of the swimmingpool. And, in any case, even when the system operates in steadyconditions, the above described preliminary dilution jeopardises acompletely satisfactory result, i. e. a homogeneous product spreading.

SUMMARY OF THE INVENTION

The main object of the present invention is to provide an apparatus fordosing a powdered or granulated additive in a water works, namely aswimming pool, which allows a direct dilution of the additive in thewater works, thus avoiding the above described drawbacks caused by thepresence of preliminary dilution means.

A particular object of the present invention is to provide an apparatusof the above mentioned kind, which allows the accomplishment of aneffective and homogeneous spreading of the product with a simplestructure, which can be easily operated.

A further object of the invention is to provide an apparatus of theabove mentioned kind, in which the possibility that ducts may be cloggedis minimised and so the machine stops for maintenance operations and/orreplacements of worn out components are reduced.

Said objects have been achieved with the apparatus for dosing powderedor granulated additives in water works according to the presentinvention, the main features of which are defined in the first of theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the apparatus for dosing powdered orgranulated additives according to the present invention will be apparentfrom the following description of one of its embodiments, to be intendedonly as an example and not a limitation, with reference to the attacheddrawings in which:

FIG. 1 shows a side view of the dosing apparatus according to thepresent invention;

FIG. 2 is a front view of the dosing apparatus of FIG. 1;

FIG. 3 shows a side view, with sectioned and/or broken parts, of thedosing assembly of the apparatus of FIGS. 1 and 2;

FIG. 4 is a front view, with sectioned and/or broken pares, of thedosing assembly of FIG. 3;

FIG. 5 shows a top plan view of the dosing assembly of FIGS. 3 and 4;

FIG. 6 is shows an intermediate cross section view of a manifold used inthe dosing assembly of FIGS. from 3 to 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference in particular to FIGS. 1 and 2, a dosing apparatusaccording to the present invention comprises a box-shaped outer frame 1,made of a plastic material, having supporting and covering functions.Frame 1 comprises a lower container 2, standing from an enlarged base 2a, and a feedbox 3, upwards supported by lower container 2 and capableof collecting and conveying the powdered or granulated additive to bedosed. Feedbox 3 comprises a funnel-shaped lower section 3 a, entirelyplaced within lower container 2 and ending with a port facing the bottomthereof, and an upper collar 3 b, external to the container, closed by acover 4.

Cover 4 has an upper opening 7, closed by a removable cap 8, throughwhich the additive is poured into feedbox 3, and a housing 9 whosefunction will be made clearer hereinafter. Respective windows 5 areformed in two opposite side walls of lower container 2. Windows 5, eachclosed by a removable plate 6, permit the access to the inside ofcontainer 2 for the maintenance and/or the checking of the componentshoused therewithin.

Within container 2 it is in fact placed a dosing assembly, generallyindicated at 10, schematically shown with faint lines in FIGS. 1 and 2,and in detail in FIGS. 3 to 6. With reference in particular to thelatter, dosing assembly 10 comprises a delivery element 11, generallycylindrical and horizontally extending, the side surface of which,having an incomplete development, forms an upward flat face 11 a. Acylindrical seat 12 is axially formed in element 11 and communicateswith the outside of the element itself via a cavity 13, which opens inflat face 11 a. In particular, cavity 13 communicates with the inside offunnel-shaped lower section 3 a of feedbox 3 through its downward port,thus allowing the discharge of the powder into axial seat 12. To assistsuch discharge cavity 13 provides two opposite skew faces 13 a,converging to seat 12.

A shaft 14 rotates within axial seat 12, supported by bushings 15 a, 15b with ceramic seals and operated by a motor reducer 38. The sidesurface of shaft 14 is screwed so that it conveys the powder towards acollection chamber 16, conically shaped, formed in the front face ofelement 11 adjacent to bushing 15 b. A passage 17, radially extendingfrom chamber 16, lets the powder fall therefrom to the upward opening ofa substantially tubular manifold 18, which will be described in detailhereinafter. A hole 40, radially formed in element 11, also opens intochamber 16. A duct 41 for feeding air to chamber 16 is coaxially engagedwithin hole 40.

A constant level tank 19, substantially parallelepiped shaped with apartially open top, is placed under delivery element 11. Water isdischarged into tank 19 through a couple of inflow pipes, respectivelyindicated at 20 and 21, resulting from a T-junction with a main inflowpipe 37. Inflow pipes 20 and 21 open in a side wall 19 a of tank 19,near the upper side thereof, at slightly different heights (in thefigures, 20 indicates the higher inflow pipe), and are provided withrespective check valves, not shown. The opening of the valves isoperated by levers 24 and 25, controlled by respective floats 22 and 23,connected to the free ends thereof.

A circular opening 26 is formed in She top wall of tank 19, forengagement with manifold 18, shown in particular in FIG. 6. Manifold 18comprises a lower tubular body 27, with a lower, narrower section 27 adischarging into tank 19, and an upper, wider section 27 b within whichlower section 27 a part-ally extends with a segment 27 c. The segmentdefines, in co-operation with the bore of upper section 27 b, an annularhollow space 28. Manifold 18 further comprises an open bottomed cup 29,into which the powder is discharged from passage 17, perimetricallysupported by the free edge of upper section 27 a of body 27. The openbottom of cup 29 is in part fitted within segment 27 c. internallyfunnel shaped, so as to define an annular meatus 30 which communicateshollow space 28 with the inside of lower section 27 a of body 27.

A tapping duct 31 extends between the inside of inflow pipe 20, i.e. theslightly higher one, and hollow space 28, via a hole 32 formed in thebottom of the latter.

Tank 19 is also connected with an outflow pipe 33, opening in wall 19 atoo, near the bottom of the tank itself. The water collected inside tank19 is delivered through pipe 33, by means of a pump 34, to the waterworks to be fed. Finally, a pipe 36 sideways discharges into tank 19,for bringing in a pH-controlling agent, delivered by a vibration pump35, schematically shown in FIG. 7.

A microprocessor controlled electronic assembly, not shown, with therelevant operation keys, is placed in housing 9, for operating,according to programmable time sequences, motor reducer 38, shaft 14,pump 34 and pH-controlling vibration pump 35 through a cable system, notshown either. The cable system is intercepted by a panel 39 ofconnecting terminals, placed on a side wall of lower container 2. Panel39 permits the connection of external instruments, provided with meansfor reading the parameters to be controlled in the water works andsuitable to permit, on the basis of the signals transmitted by saidmeans, an automatic feedback control of the dosing apparatus.

The dosing apparatus according to the present invention works in thefollowing way. The disinfectant powder is loaded into feedbox 3 throughopening 7 of cover 4 and comes in this way to dosing assembly 10,filling cavity 13 of delivery element 11. The rotation of shaft 14,thanks to its screwed profile, forces the powder towards chamber 16,from which it is dropped into cup 29 of manifold 18 through passage 17.

Rotation and stop times of shaft 14, the rotation speed of which is keptconstant, establish the amounts of dosed powder and are automaticallycontrolled, according to pre-programmed instructions on themicroprocessor electronic assembly, to keep the desired additivepercentage in the water of the works (e.g. in case of swimming poolsabout 0.6÷1 ppm)

Air feeding into chamber 16 via duct 41 prevents any possiblecementation of the additive, effect of the moisture it naturally tendsto absorb, thus avoiding an unsmooth running or even a stop of shaft 14.Said air feeding can be provided by means of the connection of duct 41to the air cooling system of pump 34 or, alternatively, to a smallauxiliary fan.

Contemporaneously inflow water, preventively filtered according to anyconventional method, e.g. with activated carbon, enters tank 19 throughinflow pipes 20 and 21. From pipe 20 a part of the water is tapped viaduct 31 and brought into annular hollow space 28 of manifold 18. From itwater overflows throughout meatus 30, creating a turbulence whichassists its mixing with the additive dropped through passage 17. Then,the additive-mixed water goes down, through lower section 27 a of body27, into tank 19, where it meets the already present water, to be takenaway and fed to the water works via outflow pipe 33, thanks to pump 34.

Float 22, controlling the flow through inflow pipe 20, stops the samewhen the water level in the tank overcomes a predetermined value. Whensaid level decreases, to prevent pump 34 from idling, with all theinvolved inconveniences, float 23 opens also inflow pipe 21, placed in alower position to establish a different intervention level. A higheramount of water is then brought into the tank and the level quicklyreturns to a value which permits a regular running of the pump.

Similarly, to keep the pH in the works at a desired value, the timedinlet of the relevant agent to tank 19, via pipe 36 and by means ofvibration pump 35, is controlled. More specifically, the pH controllingagent shall be delivered so as to avoid its mixing with the disinfectantadditive, whereby a possible chemical incompatibility between the twoagents does not involve functional and workers' safety problems. Thementioned expedient is in any case sufficient to achieve the purpose,and, due to the particular dilution method, no complex check andsecurity systems are needed.

The worker can check regularly, by means of suitable reading means, theadditive percentage and the pH in the water of the works and, as afunction of the read values, can turn off the pre-determined controlprogram and directly operate the delivery, for example increasing thatof the additive if a long stop has caused its percentage to fall down.In the same way, as above mentioned, the connection of suitableinstruments to panel 39 allows the turning off of the time sequencecontrol program and the automation of a feedback dosing.

It will be apparent in light of the above that the frequency of cleaningand maintenance interventions, both on dosing assembly 10 and on theoutflow system, is very low. In fact the flow fed to the works throughpipe 33 is substantially constant, apart from the amount ofadditive-mixed water delivered by manifold 18. Besides, the highturbulence generated within manifold 18, thanks to its specialstructure, prevents deposits of solid material from forming on the wallsthereof, which would reduce the water flow section. The possibleformation of deposits is in any case strongly inhibited thanks to theinflow to tank 19, via pipe 36, of the pH controlling agent.

Whenever necessary, to lower the pH value further in the outflow pipingand in the whole water works, carbon dioxide can be added downstreampump 34, by means of automatically or semiautomatically controlledfeeders. It is to be noted in this connection that, as an example, theregulations related to the field of swimming pools prescribe that the pHof the water shall be comprised between 7.2 and 7.6.

To assist the rotation of shaft 14, bushings 15 a, 15 b, as well asdelivery element 11 are preferably made of polypropylene, whereas shaft14 itself is made of delrin™.

The dosing apparatus according to the invention is, as above said,particularly suitable for use in the field of swimming pools. In thiscase the disinfectant substance is typically a mixture containing 65 inweight of calcium hypochlorite and 35% of inert material. Since thisadditive, as well as other chlorine based ones, is chemically veryactive, the components which come directly into contact with it, such asfeedbox 3, are made of a plastic material having a high resistance tocorrosion (e.g. polystyrene).

The advantages brought by the use of the dosing apparatus according tothe invention will be apparent from the above. By the way, apart fromthe already cited savings in operation and maintenance costs, allowsproduct savings up to 60% with respect to the conventional systems. Thisbecause, since the product is not subject to any preliminary dilution,it can be actually preserved and a much lower amount thereof is neededto accomplish the same results in term of disinfectant action quality.

Namely in the case of use in swimming pools, thanks to the direct, quickand effective mixing of the product with water, the dosing apparatuspermits to accomplish an homogeneous product spreading throughout thewhole volume of the pool in a very short time. Besides, the workersnever come into contact with water containing a high additivepercentage, like that in the preliminary tank of the known system,whereby they can work in more comfortable and safer conditions.

Other variations and/or modifications that can be brought to theapparatus for dosing powdered or granulated additives in water works,namely swimming pools according to the invention fall within the scopeof the invention itself as stated in the appended claims.

What is claimed is:
 1. An apparatus for dosing a powdered or granulatedadditive in a water works, comprising a dosing assembly (10)hydraulically connected to said works, and means (3) for containing saidadditive, capable of conveying said additive towards said dosingassembly (10), said dosing assembly comprising: water collecting means(19) hydraulically connected to at least one inflow (20, 21) of unmixedwater and to at least one outflow (33) of additive-mixed water; means(24, 25) for controlling said water inflow; pump means (34) forsupplying water through said outflow; and means (11) for delivering saidadditive from said containing means (3) towards said water collectingmeans (19), said dosing assembly also comprising a manifold (18)arranged over said water collecting means (19) and over a means (31) fortapping said unmixed water from said inflow to said manifold (18), themanifold comprising a lower, narrower tubular section (27 a),communicating with said water collecting means (19) and an upper, widertubular section (27 b), within which said lower section (27 a) partiallycoaxially extends, so that between the two sections an annular hollowspace (28) is defined, said tapping means (31) being hydraulicallyconnected with said hollow space (28), said manifold (18) furthercomprising an upper, open bottom cup-shaped body (29), into which saidadditive is discharged from above, said body being fitted within saidlower section (27 a) so as to defined in cooperation therewith anannular meatus (30), whereby said additive mixes with water flowingthrough said meatus (30), and additive mixed water is discharged intosaid collecting means (19).
 2. The apparatus according to claim 1,wherein said lower section (27 a) of said manifold (18) comprises anupper side (27 c) having a funnel-shaped inner surface.
 3. The apparatusaccording to claim 1, wherein said additive delivering means (11)comprise a delivery element (11), in a seat (12) of which screwed means(14) are rotatably supported, said seat (12) being communicated withsaid additive collecting means (3) and with said manifold (18) viarespective passages (13, 17) formed in said element, whereby therotation of said screwed means (14) within said seat (12) causes theadditive to convey into said manifold (18).
 4. The apparatus accordingto claim 3, wherein said seat (12) is substantially cylindrical and saidscrewed means (14) comprise a shaft (14) rotatable therein, said shaftbeing formed in said delivery element (11) with an axis of rotationsubstantially orthogonal to said passages (13, 17) and an axis of saidmanifold (18), said manifold (18) radially extending from said seat(12).
 5. The apparatus according to claim 4, wherein a conical shapedchamber (16) for collecting said additive is formed in said deliveryelement, coaxially to said seat (12) and downstream thereof.
 6. Theapparatus according to claim 4, wherein air feeding means (41) areassociated to said delivery element (11), to keep said additive drywithin said delivery element (11).
 7. The apparatus according to claim6, wherein said air feeding means comprise a duct (41) coaxiallyengaging within a hole (40) formed in said delivery element (11).
 8. Theapparatus according to claim 1, wherein said water collecting meanscomprise a constant level tank (19), hydraulically communicated with twoinflows (20, 21) of unmixed water and with said outflow (33) ofadditive-mixed water to said works, said means (24, 25) for controllingsaid water inflow being operated by respective float means (22, 23),said inflows (20, 21) being placed at different heights with respect tothe bottom of said tank (19), said tapping means (31) being connected tothe higher inflow (20).
 9. The apparatus according to claim 8, whereinsaid manifold is engaged within a circular opening (26) formed in acover wall of said tank (19).
 10. The apparatus according to claim 1,wherein means (35) for dosing a pH reducing agent are hydraulicallyconnected to said water collecting means (19).